As close to erect as a penis can possibly get without standing up or sticking out. The state of full hanging engorgement.
The optimum conditions for a soft core full frontal Playgirl photo shoot.
Deceiving because one assumes that if it's still hanging down it's gonna be bigger standing up when in fact that's all there is.

Cinema appreciator 1: "You saw the end of Boogie Nights, little Marky Mark is hung like a bull moose!"
Cinema appreciator 2: "The hell he is! That was maximum tumescence in repose."